averages Model Questions & Answers, Practice Test for ssc cgl tier 2

Answer: (c)

Let the present age be x yrs. Then

125% of (x – 10) = x; and $83{1}/3$ % of (x + 10) = x

∴ 125% of (x – 10) = $83{1}/3$ % of (x + 10)

$5/4(x = 10) = 5/6(x + 10)$

or, $5/4x - 5/6x = 50/6 + 50/4$

or, ${5x}/12 = 250/12$

∴ x = 50 yrs.

Answer: (b)

Check as follows,

${1 + 2 + 3 + 4 + 5}/5 = 3$

${1 + 2 + 3 + 4 + 5 + 6 + 7}/7 = 4$

Answer: (c)

Radha's Age = A

Rani's Age = B

${A - 5}/{B - 5}$ = 3 ⇒ A - 5 = 3(B - 5)...(i)

${A - 1}/{B - 1}$ = 2 ⇒ A - 1 = 2(B - 1)...(ii)

from equation (i) and (ii)

⇒ – 4 = B – 13 ⇒ B = 9

So A – 1 = 18 – 2⇒ A = 17

A – B = 17 – 9 = 8 years

Answer: (a)

Let the no. of boys = x

No. of girls = 150 – x

Average weight = ${70x + (150 - x) × 55}/150$

⇒ 60 = ${70x + (150 - x) × 55}/150$

No. of boys (x) = 50

No. of girls = 150 – x = 150 – 50 = 100

Answer: (c)

Average of five consecutive even numbers or odd numbers is the middle term.

In this case, the average is c.